test: reinstate lndhc playground build

it broke after last commit where lnd client got moved into the lightning
module, preventing lndhc from importing it.

also, add lndhc to CI build to catch regressions like this early on.

.woodpecker.yml

@@ -32,4 +32,4 @@ pipeline:
   playground:
     image: git.qcode.ch/nakamochi/ci-zig0.11.0:v2
     commands:
-      - zig build guiplay btcrpc
+      - zig build guiplay btcrpc lndhc

build.zig

@@ -175,7 +175,7 @@ pub fn build(b: *std.Build) void {
             .optimize = optimize,
         });
         lndhc.strip = strip;
-        lndhc.addModule("lndhttp", b.createModule(.{ .source_file = .{ .path = "src/lndhttp.zig" } }));
+        lndhc.addModule("lightning", b.createModule(.{ .source_file = .{ .path = "src/lightning.zig" } }));
 
         const lndhc_build_step = b.step("lndhc", "lnd HTTP API client playground");
         lndhc_build_step.dependOn(&b.addInstallArtifact(lndhc, .{}).step);

src/test/lndhc.zig

@@ -1,5 +1,5 @@
 const std = @import("std");
-const lndhttp = @import("lndhttp");
+const lndhttp = @import("lightning").lndhttp;
 
 pub fn main() !void {
     var gpa_state = std.heap.GeneralPurposeAllocator(.{}){};